US3508852A

US3508852A - Oil burner

Info

Publication number: US3508852A
Application number: US695215A
Authority: US
Inventors: Avinoam Hourwitz; Boleslaw Houchman
Original assignee: Individual
Current assignee: Individual
Priority date: 1967-01-04
Filing date: 1968-01-02
Publication date: 1970-04-28
Anticipated expiration: 1987-04-28
Also published as: AT287895B; FR1549916A; ES349261A1; NL6800066A; NO117255B; BE708948A; CH459437A; DK116080B; DE1601267A1

Description

A ril 28, 1970 A, HouRwlTg ET AL 3,508,852

OIL BURNER Filed Jan. 2. 1968 FIG. 1

FIG. 3

INVENTOR N A M w w/W H Z n W R U 0 H M A O W V A BOU- FIGA

ATTORNEY United States Patent Office 16 Int. Cl. F23d 11/04 US. Cl. 431168 6 Claims ABSTRACT OF THE DISCLOSURE A burner comprising a chamber in which is disposed a rotary cup mounted on a hollow rotating shaft through which supply fuel is delivered to the cup and ejected therefrom in atomized form, the ejected fuel being vapourized in a first region of the chamber and ignited in a second region thereof, a fan for aspiring air to be mixed with the vapourized fuel, a cover spaced above the rotary cup, and a fixed body in the form of a conical plate surrounding and spaced outwardly from the rotary cup and cover, the plate being located in the trajectory of the ejected fuel and having air passages for the aspired air disposed in the second region of the chamber.

BACKGROUND OF THE INVENTION Field of the invention The present invention relates to 'a burner unit of the type in which the fuel is atomized by ejection from a rotary cup.

Description of the prior art Burners are known comprising a chamber in which is disposed a rotary cup mounted on a hollow rotating shaft through which supply fuel is delivered to the cup and ejected therefrom in atomized form, the ejected fuel being vapourized in a first region of the chamber and ignited in a second region thereof, and a fan for aspiring air to be mixed with the vapourized fuel. See for example British patent specification 822,288. However the performance of the known burners is not quite satisfactory in several respects. The blast flame frequently produces soot which is in part deposited in the heat exchanger and flue. Also, a continuous hum is frequently heard during the operation of the burner. In addition, startingup the burner may be accompanied by a loud noise together with an ejection of smoke caused by the explosion and incomplete combustion of residue fuel already in the burner.

Objects of the present invention are to provide improvements in one or more of the above respects in a burner unit of the rotary cup type.

SUMMARY OF THE PRESENT INVENTION According to the invention, the burner of the foregoing type includes a cover spaced above the rotary cup, and a body surrounding and spaced outwardly from the rotary cup and the cover. This body is located in the trajectory of the ejected fuel and has air openings in the path of the aspired air. The body is spaced at such distance from the rotary cup that the air openings are located in the second region (i.e. where the fuel is ignited) of the chamber and also in the trajectory of the ejected fuel, whereby freshly arrived vapourized fuel is ignited immediately upon meeting the air in the vicinity of said air openings.

It has been found that with this arrangement the resulting flame is completely blue and virtually no soot is produced, and further that the fuel burns without humming.

Patented Apr. 28, 1970 According to another feature, the burner may include a conduit for introducing start-up fuel to the ignition device before the supply fuel arrives at the rotating cup, the flow of the start-up fuel being discontinued after the supply fuel is ignited. This feature has been found to solve the problem of the loud noise and the ejection of smoke usually occurring upon starting-up the known burners.

BRIEF DESCRIPTION OF THE DRAWINGS The invention is illustrated, by way of example only, in the accompanying drawings in which FIGS. 1 and 2 show in elevational section two forms of a burner unit according to the invention; FIG 3 schematically shows the circuit that may be used for the unit of FIG. 2; and FIG. 4 shows a modification of the burner unit.

DESCRIPTION OF THE PREFERRED EMBODIMENT The burner unit illustrated in FIG. 1 comprises a supporting casing 1 merging into a superposed sleeve part 2. Casing 1 comprises a core 3 supporting an electric resistor 4 coiled on a refractory support and serving as the ignitor. A hollow shaft 7 whose lower portion is connected to an electric driving motor (not shown) passes through bores 5 and 6 in the bottom of the casing and the core, respectively. The lower end of shaft 7 is connected to a fuel supply. Keyed on shaft 7 is a fan 8 rotatable within a hollow space 9 of easing 1 and serving for the aspiration of air through a plurality of bores 10 provided in the bottom of casing 1, the aspired air being delivered through ducts 12 for admixture with the fuel.

Mounted on the upper, delivery end of shaft 7 and in chamber 13 of the burner is a rotary cup 14 which is covered from above by means of a tray-shaped cover 15 supported by a ring 16 resting on stays 17. The

aggregate

15, 16, 17 is surrounded by a fixed annular or conical plate or bowl 18. The wall of bowl 18 is inclined so as to be in the trajectory of the fuel ejected from cup 14 and is formed with a plurality of openings or vents 19 arranged in a circular array around cup 14 and cover 15 and also in the trajectory of the ejected fuel. Each vent 19 is surrounded by a rim 20. Bowl 18 rests on a sleeve 21, there being an annular free space 22 between sleeve 21 and heater 4 merging below into a space 23 of increased diameter. A duct 24 from space 23 is connected to a tube 25 and serves as a return to the fuel supply of any non-burnt fuel. On the flame producing side of bowl 18 is mounted a deflector 26 for the concentration and direction of the blast flame.

The operation of the burner unit is as follows: When shaft 7, fan 8, and rotary cup 14 rotate, fuel is delivered from the fuel tank through the shaft to the rotary cup 14 and is ejected into chamber 13 in atomized form. At the same time the rotation of fan 8 causes air to flow through ducts 10, ducts 12 and openings 19.

At the beginning of the operation the fuel is ignited by resistor coil 4 and thereafter the flame maintains itself by the continuous supply of fuel and air. The flame surrounds cover 15 which is therefore in a hot state throughout the operation of the burner. In consequence, chamber region 13' is heated and the atomized fuel ejected from the rotary cup 14 is vapourized therein. The temperature of chamber region 13" in which combustion takes place is higher, suflicient to sustain combustion of freshly arriving vapourized fuel. Any non-vapourized fuel impinging on bowl 18 drips down through

spaces

22 and 23, and is returned through duct 24 to the fuel tank. The returning liquid fuel is prevented from dripping through vents 19 by rims 20.

The vapourized fuel delivered from region 13 impinges on the surface of bowl 18 in the vicinity of openings 19. The location of bowl 18 is such that openings 19 are located in chamber region 13 where the temperature is sufiiciently high to sustain combustion of the freshly arriving vapourized fuel. The latter is therefore ignited as soon as it meets the air passing through the openings. Because this ignition occurs simultaneously with the meeting of the vapourized fuel and air, a soot-free silent blue flame is produced. Moreover, since any non-vapourized fuel that there may be is returned to the tank and does not participate in the combustion, this also contributes to the soot-free, blue character of the flame.

In starting-up, the current to the ignitor resistance is switched on a short time before the fuel arrives at the cup. Thus when fuel starts dripping from the cup the resistor is already hot and glowing. It was found that the fuel which remained in the vicinity of the cup on the metal parts of the burner at the time the resistor coil was ignited sometimes caused a small explosion, or a smouldering of the fuel, which gave rise to an especially loud noise, and/or an ejection of smoke from the burner.

These undesirable effects are avoided by the modification illustrated in FIG. 2. Here an oil conduit 30 is provided, terminating in a spout 31 overlying the ignitor resistor 32, which in this case is positioned eccentrically in relation to the rotating shaft 7 of the burner. A concentric resistor, such as resistor 4 in FIG. 1, could of course also be used. In FIG. 2, the deflector 26 is omitted, but the remaining parts are the same as in FIG. 1 and therefore have been referred to by the same reference numerals.

The electrical wiring for operating the burner of FIG. 2 is schematically illustrated in FIG. 3. It includes a switch 35 which permits the flow of current to the ignitor resistance (4 or 32). The motor M for driving shaft 7 and the pump P for supplying the starting fuel through conduit 30 are controlled through a time-delay device TD (eg a slow-acting relay) such that: the ignitor resistor is first heated; a short time thereafter the starting fuel is pumped through conduit 30 so as to drip onto the glowing heater and to ignite; and then a short time thereafter the supply fuel arrives at the rotating cup 14 and is vapourized and ignited in the manner described earlier. Once the supply fuel is ignited, the electric current to the ignitor and also to the pump for the starting fuel are both switched olf by a control switch 36. The latter may be operated in a known manner, e.g. after a predetermined time delay, or in response to the air pressure created by the fan or the burner. Instead of pumping the starting fuel by a pump, it may be gravity-fed and controlled by a valve.

While the cover 15 in FIGS. 1 and 21s shown as being fixed to body 18, it could also be fixed (by stays equivalent to 17) to cup 14 so as to rotate therewith, whereupon the cover is preferably dished outwardly, instead of inwardly as shown in FIGS. 1 and 2, and may be of approximately the same diameter as the cup. This is illustrated in FIG. 4, wherein it is seen that the cover 15 is of outstay 17' so that it"rotates with the cup.

Further variations and embodiments of the invention will be apparent.

What is claimed is:

1. A burner comprising a chamber in which is disposed a rotary cup mounted on a hollow rotating shaft through which supply fuel is delivered to the cup and ejected therefrom in atomized form, the ejected fuel being vaporized in a first region of the chamber and ignited ina second region thereof, and a fan for aspiring air to be mixed with the vaporized fuel, characterized in that said burner includes a cover spaced above the rotary cup, and a fixed annular body surrounding and spaced outwardly from the rotary cup, said fixed annular body having a wall inclined with respect to the rotary cup and being formed with a circular array of openings for the aspired air surrounding said cup and cover, the said annular body and the circular array of air openings therein being located in the trajectory of the ejected fuel and in said second region of the chamber whereby freshly arriving vaporized fuel is ignited immediately upon meeting the air passing through said air openings.

2. A burner as defined in claim 1, wherein said fixed annular body is in the form of a conical plate surrounding the rotary cup and cover.

3. A burner as defined in claim 1, wherein each air opening is surrounded on the flame producing side of said body with a rim adapted to prevent the dripping of any non-vaporized fuel through the opening.

4. A burner as defined in claim 1, wherein said cover is fixed to said body.

5. A burner as defined in claim I, wherein said cover is fixed to said rotary cup so as to rotate therewith.

6. A burner as defined in claim 1, further including a start-up ignition device, a conduit for introducing startup fuel to said ignition device before the supply fuel arrives at the rotating cup, and means for discontinuing the flow of the start-up fuel after the supply fuel is ignited.

References Cited UNITED STATES PATENTS 396,525 1/1889 Bains 431 210 855,688 6/1907 Blubaugh 431-285 1,497,829 6/1924 Allen et a1 431-168 X 1,544,208 6/1925 Bennett 239 214.13 1,695,030 12/1922; Scheminger 431168 2,374,290 4/1945 Johansson 431 117 x 2,507,006 5/1950 Hammellet al. 239 214.17

FOREIGN PATENTS 644,522 7/1962 Canada.

EDWARD G. FAVORS, Primary Examiner US. Cl. X.R.